Tech: Williams System 6 Running on System 7 MPU

[Jim Knight]

I know that the conventional wisdom is that there is forward compatability
from System 3 up to System 7

I also realize that there are limitations in backward compatability of a
System 7 MPU running a System 3 game as there are no DIP switches etc.

Also, I realize that the System 3-6 software needx to be resized to fit the
larger System 7 ROMs and that there is different addressing ranges for
System 7 games.

However, my interest lies primarally in the compatability of the RAM and
CMOS RAM addressing between System 7 and earlier boards.

So, my question is has anyone actually put a System 3, 4 or 6 software into
a System 7 MPU (after massaging for ROM sizing) and had it work?

Jim Knight
734 330 5543

[Chris]

....probably not the answer you are looking for, but I have Firepower ROMS
running in a system 7 MPU in my Firepower. Yes, I'm sure that's NOT the
answer you are looking for.

Chris

Post by Jim Knight
I know that the conventional wisdom is that there is forward compatability
from System 3 up to System 7
I also realize that there are limitations in backward compatability of a
System 7 MPU running a System 3 game as there are no DIP switches etc.
Also, I realize that the System 3-6 software needx to be resized to fit
the larger System 7 ROMs and that there is different addressing ranges for
System 7 games.
However, my interest lies primarally in the compatability of the RAM and
CMOS RAM addressing between System 7 and earlier boards.
So, my question is has anyone actually put a System 3, 4 or 6 software
into a System 7 MPU (after massaging for ROM sizing) and had it work?
Jim Knight
734 330 5543

[Jim Knight]

Thanks. I think that is exactly what I need.

You have Firepower ROMS (System 6) running in a System 7 MPU. Whether it is
running in a System 6 or 7 game should be transparent to the MPU.

Crud. Now I have to do some more homework.

Jim Knight

PS. Thanks again.

Post by Chris
....probably not the answer you are looking for, but I have Firepower ROMS
running in a system 7 MPU in my Firepower. Yes, I'm sure that's NOT the
answer you are looking for.
Chris

Post by Jim Knight
I know that the conventional wisdom is that there is forward compatability
from System 3 up to System 7
I also realize that there are limitations in backward compatability of a
System 7 MPU running a System 3 game as there are no DIP switches etc.
Also, I realize that the System 3-6 software needx to be resized to fit
the larger System 7 ROMs and that there is different addressing ranges
for System 7 games.
However, my interest lies primarally in the compatability of the RAM and
CMOS RAM addressing between System 7 and earlier boards.
So, my question is has anyone actually put a System 3, 4 or 6 software
into a System 7 MPU (after massaging for ROM sizing) and had it work?
Jim Knight
734 330 5543

[Chris]

Good, I really thought I did not answer your question. Glad I could help!

Chris

Post by Jim Knight
Thanks. I think that is exactly what I need.
You have Firepower ROMS (System 6) running in a System 7 MPU. Whether it
is running in a System 6 or 7 game should be transparent to the MPU.
Crud. Now I have to do some more homework.
Jim Knight
PS. Thanks again.

Post by Chris
....probably not the answer you are looking for, but I have Firepower
ROMS running in a system 7 MPU in my Firepower. Yes, I'm sure that's NOT
the answer you are looking for.
Chris

Post by Jim Knight
I know that the conventional wisdom is that there is forward
compatability from System 3 up to System 7
I also realize that there are limitations in backward compatability of a
System 7 MPU running a System 3 game as there are no DIP switches etc.
Also, I realize that the System 3-6 software needx to be resized to fit
the larger System 7 ROMs and that there is different addressing ranges
for System 7 games.
However, my interest lies primarally in the compatability of the RAM and
CMOS RAM addressing between System 7 and earlier boards.
So, my question is has anyone actually put a System 3, 4 or 6 software
into a System 7 MPU (after massaging for ROM sizing) and had it work?
Jim Knight
734 330 5543

[o***@freesurf.ch]

Post by Jim Knight
I know that the conventional wisdom is that there is forward compatability
from System 3 up to System 7
I also realize that there are limitations in backward compatability of a
System 7 MPU running a System 3 game as there are no DIP switches etc.
Also, I realize that the System 3-6 software needx to be resized to fit the
larger System 7 ROMs and that there is different addressing ranges for
System 7 games.
However, my interest lies primarally in the compatability of the RAM and
CMOS RAM addressing between System 7 and earlier boards.
So, my question is has anyone actually put a System 3, 4 or 6 software into
a System 7 MPU (after massaging for ROM sizing) and had it work?

This works perfectly. A system 7 board has more ram space. And it has
the ram space at different adress locations. But to be backward
compatible with system 6 and system 3,4 game roms, the system 7 board
maps a part of his ram space to excat the same location as the system 6
board. So you really can adress the same ram space on a system 7 board
with two different adress locations. If you need more information, mail
me, I have the excat adress locations somewhere at home...
Greetings Oliver
My collection: early bally and williams with custom game roms and a
nine*ball

My homepage: http://www.pinball4you.ch


mail to: okaegi at freesurf dot ch

[s***@excite.com]

Post by o***@freesurf.ch
This works perfectly. A system 7 board has more ram space.

Additionally Jim you can strap the sys7 to run with the same roms if
you want to, and you can add in the dips if you need them, and the diag
LED's. Nice board to have for testing purposes with the right roms in
the correct types you can test any williams machine with it.

The early sys7 boards have the dips and the leds already installed.

-scott CARGPB#29
RIP edloco CARGPB#9